Single crystals of V amylose

Single crystals of V amylose were prepared from dilute solution in water/ethanol over a range of temperatures. The effects of crystallization temperature on crystal morphology and thickness were investigated using transmission electron microscopy. Annealing of these crystals gave rise to large increases in crystal thickness. It is concluded that V amylose crystals behave in a similar way to crystals of linear synthetic polymers.     

Single crystals of V amylose complexed with isopropanol and acetone

Single crystals of amylose complexed with isopropanol or acetone were prepared by adding these precipitants to a metastable aqueous solution of amylose. With both precipitants, similar micrometre sized platelet crystals were obtained. They gave indistinguishable electron diffraction diagrams which could be indexed in an orthorhombic unit cell, with a = 28.26 A, b = 29.30 A, c = 8.01 A and in a space group P2(1)2(1)2(1) or P2(1)2(1)2. Within the unit cell, the amylose chains are organized in antiparallel pairs of parallel 6(5) amylose helices occupying 70% of the cell content, the remaining 30% consisting of isopropanol/acetone and water, with an estimate of 10 isopropanol/acetone molecules for 52 water molecules per unit cell. If the crystals are suspended in pure isopropanol at various temperatures or in pure methanol at room temperature, they undergo a de-solvation process that ultimately converts them into VH amylose. De-solvation with isopropanol left the crystals intact whereas with methanol, they became cracked during the shrinkage. An explanation is proposed for such difference.     

Activity and action pattern of Bacillus licheniformis alpha-amylase in aqueous ethanol

A purified B. licheniformis alpha-amylase in a mixture of ethanol-aqueous buffer (1:1, v/v) retains half the activity shown in water alone. In ethanol-aqueous buffer (7:3, v/v) about 20% of the activity is retained. The pattern of oligosaccharides produced from amylose changed with ethanol concentration; in aqueous buffer the products are: DP 1 and 2, 33.7%; DP 3, 28.5%; DP 4, 4.4% and DP 5, 33.4%. Whereas in ethanol-aqueous buffer (7:3, v/v) the products are DP 1 and 2, 66.8%; DP 3, 17.3%; DP 4, 4.1% and DP 5, 11.8%. These results suggest that a change in substrate affinity at the active centre subsites is induced in the ethanol-aqueous buffer medium.     

A Simple Preparative Method for the Isolation of Amylose and Amylopectin from Potato Starch

The defatted starch was dispersed in NaOH (1 M) and neutralized with HCl (1 M). The amylose 1-butanol complex is adsorbed on defatted cellulose powder in the solvent system containing acetate buffer (pH 4.8, 0.1 M) ± urea (2 M) ± 1-butanol (8.5 %, v/v). The complex adsorbed on cellulose powder is separated by centrifugation (2418 g). The sediment is washed with the solvent system-I to obtain the intermediate fraction. The adsorbed amylose is eluted with urea (2 M) in acetate buffer (pH 4.8, 0.1 M). The amylose, intermediate fraction and amylopectin were precipitated with ethanol, washed free of urea and air dried. They were characterized by determining their blue value and β -amylolysis limit.     

A simple preparative method for the isolation of amylose and amylopectin from potato starch

The defatted starch was dispersed in NaOH (1 M) and neutralized with HCl (1 M). The amylose 1-butanol complex is adsorbed on defatted cellulose powder in the solvent system containing acetate buffer (pH 4.8,0.1 M) + urea (2 M) + 1-butanol (8.5%, v/v). The complex adsorbed on cellulose powder is separated by centrifugation (2418 g). The sediment is washed with the solvent system-I to obtain the intermediate fraction. The adsorbed amylose is eluted with urea (2 M) in acetate buffer (pH 4.8, 0.1 M). The amylose, intermediate fraction and amylopectin were precipitated with ethanol, washed free of urea and air dried. They were characterized by determining their blue value and beta -amylolysis limit.     

Dynamic and extensional properties of starch in aqueous dimethylsulfoxide

The effect of starch composition and concentration on the rheological properties of starch in a mixed solvent, water–DMSO, was investigated in dynamic shear and extensional mode. High amylose corn starch containing 70% amylose and 30% amylopectin, common corn starch containing 25% amylose and 75% amylopectin, and waxy corn starch containing about 99% amylopectin were used in this study. Concentrations of 2, 4, 6, and 8% (w/v) in 10% water-90% DMSO (v/v) were used for each starch type. An increase in the amylopectin content of starch from 30 to 99% caused a change in behavior from semidilute solution to viscoelastic solid at a concentration of 8% (w/v). At a concentration of 2%, an increase in the amylopectin content of starch from 30 to 99% caused a change from Newtonian to incipient gel-like behavior. Behavior at intermediate concentrations of 4 and 6% (w/v) varied from semidilute to critical gel-like with increasing amylopectin content. A power-law relaxation was observed for all concentrations of common and waxy corn starches with the slope decreasing with increase in concentrations. A 2% waxy corn starch solution displayed extension thinning behavior, while a 2% high amylose corn starch solution displayed Newtonian behavior.     

The crystal and molecular structure of VH amylose by electron diffraction analysis

The crystal and molecular structures of VH amylose were determined by a constrained linked-atom least-squares refinement, utilizing intensities measured from electron diffraction patterns and stereochemical restraints. Hexagonal platelet single crystals were grown from dilute aqueous ethanol solution and their electron diffraction diagrams analysed. These data indicated that the amylose chains were crystallized in a hexagonal lattice with a = b = 13.65 A, c (chain axis) = 8.05 A and space group P6(5)22. The best model obtained using the base plane data coupled with a stereochemical refinement yielded R = 0.24 (R' = 0.25). It corresponded to a system of left-handed 6-fold helices packed on an hexagonal net but with statistically random up/down chain disorder. A column of six water molecules was present within each helical repeat. Additionally, the gap between each pair of adjacent helices was bridged by two water molecules positioned so as to allow hydrogen bonding with chains of either sense. This proposed crystal structure differs somewhat from previous reports which invoked orthorhombic lattices and requires a regularly alternating arrangement of up and down chains to account for the intensity. Suggestions are made to account for these differences.     

Repeated use of yeast biomass in ethanol fermentation of juniper berry sugars

Summary The object of this study was to establish the possibility of using the yeast biomass separated from the fermentation broth at the end of ethanol fermentation of juniper berry sugars as an inoculum in successive batch fermentation processes. A part of the fermentation broth (10% v/v) and a suspension of yeast biomass (separated from the same broth) into the water extract of juniper berries (2 g of wet yeast biomass per liter of water extract) were used as inocula. It was shown that the suspension of yeast biomass could be used as inoculum in successive batch processes without negative effects on the kinetics and ethanol yield, but with positive effects on the capacity and economy of the bioprocess. The addition of ammonium salts at optimum levels did not affect the final ethanol concentrations (4.3–4.4% v/v), but enhanced the specific rate of ethanol production, thus reducing the process duration by about five times.     

Improvement in fermentation characteristics of degermed ground corn by lipid supplementation

With rapid growth of fuel ethanol industry, and concomitant increase in distillers dried grains with solubles (DDGS), new corn fractionation technologies that reduce DDGS volume and produce higher value coproducts in dry grind ethanol process have been developed. One of the technologies, a dry degerm, defiber (3D) process (similar to conventional corn dry milling) was used to separate germ and pericarp fiber prior to the endosperm fraction fermentation. Recovery of germ and pericarp fiber in the 3D process results in removal of lipids from the fermentation medium. Biosynthesis of lipids, which is important for cell growth and viability, cannot proceed in strictly anaerobic fermentations. The effects of ten different lipid supplements on improving fermentation rates and ethanol yields were studied and compared to the conventional dry grind process. Endosperm fraction (from the 3D process) was mixed with water and liquefied by enzymatic hydrolysis and was fermented using simultaneous saccharification and fermentation. The highest ethanol concentration (13.7% v/v) was achieved with conventional dry grind process. Control treatment (endosperm fraction from 3D process without lipid supplementation) produced the lowest ethanol concentration (11.2% v/v). Three lipid treatments (fatty acid ester, alkylphenol, and ethoxylated sorbitan ester 1836) were most effective in improving final ethanol concentrations. Fatty acid ester treatment produced the highest final ethanol concentration (12.3% v/v) among all lipid supplementation treatments. Mean final ethanol concentrations of alkylphenol and ethoxylated sorbitan ester 1836 supplemented samples were 12.3 and 12.0% v/v, respectively.Mention of brand or firm names does not constitute an endorsement by University of Illinois or USDA above others of similar nature not mentioned     

Determination of the structure and degree of polymerisation of fructans from Echinacea purpurea roots

Highly water soluble fructans have been isolated from Echinacea purpurea (L.) Moench. roots by hot water extraction and precipitation at three different ethanol concentrations (80% v/v, 60% v/v and 40% v/v). The structure of the fructans has been characterised by three analytical methods: GC of silylated oxime derivatives and partially methylated alditol acetates, respectively, as well as 13C NMR analysis. The mean degree of polymerisation (mean DP) of each fructan has been determined by the glucose/fructose ratio. E. purpurea fructans represent linear inulin-type fructans with almost exclusively beta-(2-->1)-linked fructosyl units, terminal glucose and terminal fructose. Small proportions of beta-(2-->1,2-->6)-linked branch point residues were detected. The mean DP of the fructan fractions depends on the ethanol concentration used for precipitation: the lower the ethanol concentration the higher the mean DP. Corresponding results were found with all of the three analytical methods: 80% ethanol-insoluble fructan from E. purpurea shows an average mean DP of 35, 60% ethanol-insoluble fructan of 44 and 40% ethanol-insoluble fructan of 55. The applied methods provide sufficient sensitivity to determine not only the composition and structure but also the mean degree of polymerisation of fructans.     

Liquid chromatographic separation and thermodynamic investigation of lorcaserin hydrochloride enantiomers on immobilized amylose–based chiral stationary phase

A novel liquid chromatographic method was developed for enantiomeric separation of lorcaserin hydrochloride on Chiralpak IA column containing chiral stationary phase immobilized with amylose tris (3.5‐dimethylphenylcarbamate) as chiral selector. Baseline separation with resolution greater than 4 was achieved using mobile phase containing mixture of n‐hexane/ethanol/methanol/diethylamine (95:2.5:2.5:0.1, v/v/v/v) at a flow rate of 1.2 mL/min. The limit of detection and limit of quantification of the S‐enantiomer were found to be 0.45 and 1.5 μg/mL, respectively; the developed method was validated as per ICH guideline. The influence of column oven temperatures studied in the range of 20°C to 50°C on separation was studied; from this, retention, separation, and resolution were investigated. The thermodynamic parameters ΔH°, ΔS°, and ΔG° were evaluated from van't Hoff plots,(Ink′ _versus 1/T) and used to explain the strength of interaction between enantiomers and immobilized amylose–based chiral stationary phase     

Properties of Rice Stem Extracts Obtained by Using Subcritical Fluids

Rice stems were subjected to a subcritical fluid treatment at 230 °C, using ethanol or acetone at a dilution of 0–100% in water. The obtained extracts were determined for their yield, carbohydrate content, phenolic content, DPPH radical scavenging ability, and color. The highest yield and carbohydrate content were achieved with the subcritical 20% (v/v) organic solvent, while the highest phenolic content was obtained with subcritical 80% (v/v) acetone. The highest radical scavenging ability was achieved with subcritical 60% (v/v) ethanol and 80% (v/v) acetone. The lightness of the extracts obtained with subcritical ethanol and acetone was negatively correlation with their radical scavenging ability (R=?0.85). The relationship between the lightness and phenolic content of the extracts was not significant, suggesting that other substances in the extract could also possess radical scavenging ability.     

Ethanol tolerance, sugar tolerance and invertase activities of some yeast strains isolated from steep water of fermenting cassava tubers

E kunsanmi , T.J. & O dunfa , S.A. 1990. Ethanol tolerance, sugar tolerance and invertase activities of some yeast strains isolated from steep water of fermenting cassava tubers. Journal of Applied Bacteriology 69 , 672–675.
Thirteen yeasts isolated from the steep water of fermenting cassava tubers were screened for ethanol tolerance. Three strains which showed measurable growth in medium containing 10% (v/v) ethanol were also sugar-tolerant and grew well in medium containing 25% (w/v) glucose. One of the strains, YC3, was found to possess much higher invertase activity than the other two and could be of value in ethanol production from molasses. Further search for industrially useful yeasts in African fermented foods is suggested.     

Preparation and characterization of gelatinized granular starches from aqueous ethanol treatments

In order to modify the properties of native starch granules, the formation of gelatinized granular forms (GGS) from normal, waxy, and high amylose maize, as well as potato and tapioca starches was investigated by treating granules with aqueous ethanol at varying starch:water:ethanol ratios and then heating in a rotary evaporator to remove ethanol. The modified starches were characterized using bright field, polarized and electron microscopy. Short/long range molecular order and enthalpic transitions on heating were also studied using infrared spectroscopy, X-ray diffractometry and differential scanning calorimetry respectively. A diffuse birefringence pattern without Maltese cross was observed for most GGS samples. Treatment with aqueous ethanol resulted in starch-specific changes in the surface of granules, most noticeably swelling and disintegration in waxy maize, surface wrinkling in normal maize and tapioca, swelling and opening-up in potato starches, and swelling and bursting in high amylose maize. The ratio of ethanol to water at which original granular order was disrupted also varied with starch type. GGS had less short range molecular order than native granules as inferred by comparing 1047/1022 wave number ratio from infrared spectroscopy. Similarly, A- and B-type diffraction reflections were either reduced or completely lost with evolution of V-type patterns in GGS.     

The potential pitfalls of using 1,1-diphenyl-2-picrylhydrazyl to characterize antioxidants in mixed water solvents

Approaching living systems, aqueous solutions are appropriate to characterize antioxidants, whereas the frequently used standard 1,1-diphenyl-2-picrylhydrazyl (DPPH) is insoluble in water. Therefore, mixed water-ethanol solvents were investigated using the electron paramagnetic resonance (EPR) spectroscopy. Two forms of DPPH were identified: at higher ethanol ratios a quintet spectrum characteristic of solutions, and at lower ratios, a singlet spectrum typical for solid DPPH, were found. Mixed solvents with 0-50% (v/v) water reproduced the same antioxidant equivalent points well and the reaction rate between DPPH and the antioxidant may increase considerably with increasing water ratios, as demonstrated using vitamin E as an antioxidant. But at still higher water ratios (70-90% (v/v)) the antioxidant activities dropped, since a part of the DPPH in the aggregated form does not react sufficiently with the antioxidants. Characteristics of the most common antioxidants were determined in ethanol or its 50% (v/v) aqueous solution.     

IGFR-I expression and structural analysis of the hard palatine mucosa in an ethanol-drinking rat strain (UChA and UChB)

The study analyzed the effects of chronic alcohol ingestion on the ultrastructure of the lining epithelium of the hard palatine mucosa of rats UChA and UChB (lines with voluntary alcohol consumption) in order to contribute to the understanding of the consequences of alcohol abuse for the morphology of the digestive system. Thirty female adult animals aged 120 days were divided into three experimental groups. (1) Ten UChA rats (genetically low ethanol consumer) with voluntary intake of 10% v/v (5.45 g/kg/day) ethanol solution and water. (2) Ten UChB (genetically high ethanol consumer) rats with voluntary intake of 10% v/v (7.16 g/kg/day) ethanol solution and water. (3) Ten Wistar rats with voluntary ad libitum water intake (control group). Both groups received Nuvital pellets ad libitum. The IGFR-I expression was intense in both experimental groups. The epithelial cells of the alcoholic rats UChA and UChB showed many alterations such as the presence of lipid droplets, altered nuclei, nuclei in corneum layer and disrupted mitochondria. It was concluded that ethanol intake induces ultrastructural lesions in the hard palatine mucosa.     

Isolation, structure, and characterization of the putative soluble amyloses from potato, wheat, and rice starches

Amylose, a putative linear α-(1→4)-glucan and a component of most starches, was isolated from potato, rice, and wheat starches by forming the 1-butanol complex in a solution of the starches. It previously had been found that these amyloses were incompletely hydrolyzed by β-amylase, indicating that it was partially branched. Solubilization of the butanol complex in water and steam distillation of the 1-butanol, followed by cooling to 4 °C gave precipitation of the double helical, linear, retrograded amylose over a 15 h period, leaving the soluble amylose in solution. The soluble amyloses were precipitated with two volumes of ethanol, and the precipitate was solubilized and reprecipitated to remove traces of linear amylose. The precipitated, soluble amyloses, were partially branched and had properties intermediate between linear amylose and amylopectin. The water solubility of the potato amylose was 10.52 mg/mL, with a number-average degree of polymerization (DP_n) of 8440 and 2.1% branch linkages that had a DP_n of 48; the water solubility of the rice amylose was 8.83 mg/mL, with a DP_n of 2911 and 1.4% branch linkages that had a DP_n of 72; and the water solubility of wheat amylose was 6.33 mg/mL, with a DP_n of 1160 and 1.6% branch linkages that had a DP_n of 64. The three soluble amyloses have structures and properties intermediate between the nearly water insoluble (?1 mg/mL), linear amylose, and the highly water-soluble, 4-5% branched, amylopectin.     

Evaluation of Saccharomyces cerevisiae Y5 for ethanol production from enzymatic hydrolysate of non-detoxified steam-exploded corn stover

Saccharomyces cerevisiae Y5 was used to produce ethanol from enzymatic hydrolysate of non-detoxified steam-exploded corn stover, with and without a nitrogen source, and decreasing inoculum size. The results indicated that the ethanol concentration of 44.55 g/L, corresponding to 94.5% of the theoretical yield was obtained after 24 h, with an inoculum size of 10% (v/v) and nitrogen source (corn steep liquor, CSL) of 40 mL/L. With the same inoculum size, and without CSL, the ethanol concentration was 43.21 g/L, corresponding to 91.7% of the theoretical value after 60 h. With a decreased inoculum size of 5% (v/v), and without CSL, the ethanol concentration was 40.00 g/L, corresponding to 85.8% of the theoretical value after 72 h. The strain offers the potential to improve the economy of cellulosic ethanol production by simplifying the production process and reducing the costs associated with the process such as water, capital equipment and nutrient supplementation.     

A Method for the Selective Removal of Deoxyribonucleic Acid from Tissue Sections

The deoxyrihonucleic acid (DNA) of chromatin undergoar depurinization on mild acid hydrolysis with a picric acid-formaldehyde mixture (Bouin's fluid). The apurinic acid thus formed is degraded by condensation with aniline and is lost from tissue sections, but ribonucleic acid (RNA) in nucleoli and cytoplasm is well preserved. Technique: Fi in Carnoy's fluid (ethanol:acetic acid 3:1 or ethanol:chloroform:acetic acid 6:3:1) or in aldehydes (10% formalin or 2.5% glutaraldehyde bsered to pH 7.0). Hydrolyse deparaEnii sections 12-24 hr at 27-50 C in Bouin's fluid, wash in distilled water, immerse in 25% (v/v) acetic acid, treat 1 hr at 27-30 C with 10% (v/v) dine in 25% acetic acid, wash in 25% acetic acid and then in water. Stain 10-40 min with 0₃% toluidine blue in 0.05 M potassium biphthalate bder (pH 4.0); rinse in distilled water, pass to 10% (w/v) ammonium molybdate for 1 min, rinse again in water and pass through tert-butanol and xylene to a synthetic resin. Chromatin and chromosomes are pale green; RNA in nucleoli and cytoplasm deep purple.     

Designing enzymatic kyotorphin synthesis in organic media with low water content

Design of enzymatic kyotorphin synthesis in low water media has been carried out as a function of enzyme nature, the immobilization support material and the reaction medium, by using N-benzoyl-L-tyrosine ethyl ester and L-argininamide as substrates. Native and chemically-glycated alpha-chymotrypsin deposited on supports with different degrees of aquaphilicity (celite, polypropylene PP, and polyamide PA6) were used as catalysts. Binary organic solvent systems of ethanol and different water-immiscible organic cosolvents (ethylacetate, tert-butanol, chloroform, toluene, n-hexane, and n-octane) were studied as reaction media at constant water content (3% v/v). The greater the water binding affinity of the support the lower the synthetic activity of deposited enzymes: the activity of the celite derivative was 4x greater than the polyamide derivative. The enzyme glycation process hardly modified the catalytic ability of the celite derivative, but resulted in a moderate increase in operational stability. The presence of hydrophobic organic cosolvents in the water/ethanol reaction medium significantly increased enzyme activity, whereas the selectivity of the reaction remained high. Hexane was shown to be the best cosolvent, the synthetic activity of the celite derivative in hexane-ethanol (77 : 20%, v/v) being 130x greater than that in 97% (v/v) ethanol.